1. Field of the Invention
This invention relates to process and catalyst useful in the manufacture of ketones from olefins, and more particularly to improved molybdenum sulfide catalysts useful in the vapor phase conversion of olefins to ketones.
2. Description of the Prior Art
U.S. Pat. No. 2,523,686 to W. F. Engel of Shell employs catalysts containing (1) an oxide of a metal of Groups II, III, IV or VI of the Periodic Table and (2) a metal or partially reduced oxide of a metal of Group IB, Group VII or Group VIII of the Periodic Table, and prepares saturated open-ended ketones from olefins of at least three carbon atoms per molecule in a vapor phase process in the presence of steam and under defined conditions. Dutch Pat. No. 59,179, also to W. F. Engel, relates to similar catalyst systems. The patent contains no working example to any Mo catalyst system.
U.S. Pat. No. 2,635,119 to Shell disclosed that ketones may be formed by contacting the selected olefin with a sulfide catalyst of Mo, W, Te or Se together with 0 to 40 mole percent of sulfides of Ni, Fe, or Co, in the presence of a large excess of water and at described reaction conditions. The patent contains only a single working example to a Mo sulfide (MoS.sub.3) in a liquid phase reaction of 1-octene feed to a ketone.
British Pat. No. 876,024 converts olefins into the corresponding aldehydes and ketones by passing a mixture of the olefin and oxygen, optionally with steam, over catalysts containing metal compounds whose cations and metals of a transition metal of the fifth to eighth group or first sub-group of the Periodic System and whose anions are derived from strong acids. Exemplified strong acid salts are those containing halide (Cl, Br), NO.sub.3 - and PO.sub.4.sup.=.
British Pat. No. 1,436,887 to Shell relates to a process for forming ketones in which the selected alkene is contacted with water over certain catalysts in the presence of added H.sub.2 S and in the substantial absence of O.sub.2 in order to first form a secondary mercaptan which then reacts with the water to form the corresponding ketone. The catalysts comprise supported sulfide catalysts containing one or more metals of V, Nb, Ta, Cr, Mo, W and Mn, optionally with sulfides of Fe, Co, Ni, Ru, Rh, Pd, Os, Ir or Pt as promoter. The patent indicates that the selected support can be impregnated with a decomposable sulfur compound such as ammonium thiotungstate, and ammonium heptamolybdate is said to be a highly suitable water-soluble Mo compound. After drying and calcining, the dried, calcined solids are required to be sulfided, e.g., with H.sub.2 S, mercaptans, dialkyl disulfides, S or CS.sub.2 in order to produce the catalyst.
British Pat. No. 1,495,011, also to Shell, relates to a process for forming a ketone from an alkene of 3 or more carbon atoms in which the alkene, water and H.sub.2 S are contacted in the presence of certain supported sulfided trimetallic catalysts. The catalysts contain Mo, a Group VIII non-noble metal (Fe, Co and Ni) and a Group VIII noble metal and are prepared from the corresponding metal oxides (ammonium heptamolybdate is illustrated) followed by sulfiding of the oxide solids with a mixture of H.sub.2 S and H.sub.2.
U.S. Pat. No. 4,022,837 to Chevron relates to a process for producing a ketone by contacting water and the corresponding alkene with a catalyst consisting essentially of a hydrated molybdenum (VI)-oxygen compound such as molybdic oxide (MoO.sub.3), molybdic acid, isomolybdic acid, the ammonium salts of these acids and hydrated modifications of the foregoing. During use of the catalyst, its activity for ketone formation declines, as the Mo(VI) atoms are reduced. Thereafter, the reduced Mo oxide is reoxidized to the +6 state by contacting the fixed catalyst bed with O.sub.2.
British Pat. No. 1,029,175 describes a vapor phase process in which olefin is reacted with oxygen at temperatures of less than 350.degree. C. in the presence of water vapor and a halogen, using a supported Group VIII noble metal catalyst containing either an iron, cobalt, nickel or Group I or VII transition metal compound optionally together with an alkali metal compound. Catalyst activity is stated to be further enhanced by additional use of one or more transition metal compounds of Groups III-VI, such as the rare earth metal compounds. The oxidation of propylene is indicated to give acetone as the main reaction product. Such a halide-containing catalyst system has severe disadvantages due to the corrosivity of halide-containing systems. In addition, the process of British Pat. No. 1,029,175 provides undesirably high selectivities to carbon dioxide by-product.
Thermal decomposition of various ammonium thiomolybdate salts is disclosed in U.S. Pat. Nos. 4,243,553 and 4,243,554 to Union Carbide to prepare catalysts for use in methanation and water gas shift reactions and in catalyzed hydrogenation, hydrodenitrogenation and hydrodesulfurization reactions. However, these patents do not relate to the use of the thus-prepared Mo catalysts in olefin oxidations.